Free resource before raise syntax error so we can access python file after syntax error. #3843

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1. dpgeorge commented on Jun 9, 2018

   

   dpgeorge

   on Jun 9, 2018

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   Thanks for the suggestion. What was it exactly that prompted this change?
2. tomlogic commented on Jun 17, 2018

   

   tomlogic

   on Jun 17, 2018

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   @dpgeorge, I was about to open an issue for this problem, so I can provide additional information on why I think it's a problem.

   mp_lexer_free() calls lex->reader.close(lex->reader.data);. When parsing a file on disk (e.g., foo.py as a result of import foo), we end up keeping a handle open to that file if throwing an exception in mp_parse() or fold_constants(). I'm not sure if other functions called from mp_parse() can throw an exception or not. Perhaps it's safest if mp_parse() has a wrapper that calls mp_lexer_free() and re-throws the exception? I'd like some feedback on that idea before actually implementing it, though. It seems "right" since mp_parse() already takes responsibility for freeing the lexer (and closing the reader) on success.

   I have a similar fix I plan to submit for mp_raw_code_load(), the equivalent import code path for loading .mpy files.
3. dpgeorge commented on Jun 18, 2018

   

   dpgeorge

   on Jun 18, 2018

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   @tomlogic thanks for the info. I agree with your analysis, mp_parse() does have the responsibility to free the lexer. If it didn't catch the exception then the caller would need to.
4. dpgeorge

   added a commit that references this issue on Sep 14, 2023

   py/parse: Always free lexer even if an exception is raised.

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   5e122b1
5. dpgeorge commented on Sep 14, 2023

   

   dpgeorge

   on Sep 14, 2023

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   Fixed by 5e122b1
6. dpgeorge

   closed this as completedon Sep 14, 2023
7. jprodriguez-nbs

   added a commit that references this issue on Sep 21, 2023

   py/parse: Always free lexer even if an exception is raised.

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   37854cb
8. Taccart

   added a commit that references this issue on May 23, 2026

   py/parse: Always free lexer even if an exception is raised.

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   98eaba5
9. jakub-vesely

   added a commit that references this issue on Sep 21, 2026

   py/parse: Always free lexer even if an exception is raised.

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   1f437c6